Attractiveness is most certainly subjective. While I agree with the premise of what you are saying. You went too far left field with that comment. There is no constant with attraction.
However you can understand that someone can find a person attractive while simultaneously not be attracted to them because of preference. And the more obvious, what is attractive to one person does not make it a general consensus that person is in fact, attractive. Its just preference of that particular person. Case in point, you said a rose is a beautiful flower and we all will not agree on this. Aesthetically, Tulips are more beautiful flowers but if you prefer the bloom of a Rose to base their beauty on, there are flowers whose bloom is more graceful than a Rose's.